Method of treating a textile using a colour changing form

ABSTRACT

The present invention provides a visual cue to the consumer. The visual cue is for a cleaning method, whereby a textile is treated with a liquid detergent in the form of a foam and wherin the visual cue is a colour change to said foam.

FIELD OF INVENTION

The present invention provides a consumer cue, permitting association ofa colour change with a function of the product.

BACKGROUND OF THE INVENTION

Branding is a multifaceted concept. Branding is public perception,history of a product, and association with the company who makes andmarkets the product. Branding is the product's name, its visualidentity, its packaging, and the consumer's association with the productand product quality, style, or functionality. Branding is the trust andgreater identification that consumers have in one product over another.Consumers also make judgements about brands based on learned notions.

A consumer will associate a perception with an effect even though inmany cases the perception and effect are unrelated. An example of anunrelated perception with effect is for example the use of mint intoothpaste. The mint does not effect cleaning of the teeth but theconsumer associates the taste with clean teeth.

It is known to use a robust dye in detergent powders, for example asfound in OMO™ Progress as sold in Brazil. The dye used imparts a bluecolour both to the detergent composition and an aqueous wash medium towhich the detergent composition added. The dye used maintains itsintegrity in the detergent composition as formulated and is unaffectedupon addition to an aqueous medium.

U.S. Pat. No. 5,929,004 discloses a detergent for cleaning tire wheels,which is applied in a foamy state onto the tire wheels, thereby allowinga grime adhered to the surface of the tire wheels to come off from thetire wheels. The detergent contains a surfactant, at least one alkalicompound selected from the group consisting of ammonia and aminogroup-containing alkali compounds, and a colour change indicator capableof changing its own colour when transferred from an alkaline conditionto a neutral condition.

SUMMARY OF THE INVENTION

The present invention provides a colour cue, the cue being all the morenoticeable by the consumer because the colour appears when the productis added to an aqueous medium or exposed to the atmosphere.

The colour cue of the present invention is provided by a pH dependentchromophore; the colour of the pH dependent chromophore is dependentupon the acidity or the alkalinity of its environment.

The present invention provides a method of treating a textile, thetextile carrying a stain, the method comprising the following steps: (i)applying a liquid detergent composition in the form of a foam to atextile, the liquid detergent composition comprising: a base, adetergent, a pH dependent chromophore, and carriers and adjuncts to100%; (ii) waiting until the foam, as applied, has changed colour fromits originally applied colour; (iii) rinsing the portion of the textileto which the foam has been applied with water; and, (iv) drying thetextile.

Further the method may include the step of dissolving a detergentconcentrate in water to provide the liquid detergent composition forapplication. This detergent concentrate may be selected from the groupconsisting of: liquid and granular solid detergent concentrates.

Many detergent products are formulated to a high pH and the change incolour may serve to indicate that the detergent product is functioningat the optimum pH. The colour change has other performance benefits. Thealkalinity of the composition may be tuned so that the colour changes atan preordained time. A colour change may also indicate that the textilehas been treated for sufficient time. An initial colour also providesimproved stain to treatment registration such that an environmentalbenefit is obtained because less detergent is used in cleaning a stain.

DETAILED DESCRIPTION OF THE INVENTION

The pH Dependent Chromophore

Many pH dependent chromophores are commonly referred to as indicators.However, it is not essential that the pH dependent chromophore isreversible in its colour change.

In this regard, pH dependent chromophores other than an indicator may beused. Below is found a Table in which examples of various pH dependentchromophores (indicators) are found. There are many standard textsavailable that give lists of pH dependent chromophores (indicators).Colour Colour Indicator Acid Base pKln pH range Thymol Blue - red yellow1.5 1.2-2.8 1st change Methyl Orange red yellow 3.7 3.2-4.4 Bromocresolyellow blue 4.7 3.8-5.4 Green Methyl Red yellow red 5.1 4.8-6.0Bromothymol Blue yellow blue 7.0 6.0-7.6 Phenol Red yellow red 7.96.8-8.4 Cresol Red yellow red 8.2 7.2-8.8 Metacresol yellow purple 8.327.4-9.0 purple Thymol Blue - yellow blue 8.9 8.0-9.6 2nd changePhenolphthalein colourless Pink 9.4  8.2-10.0 Thymolphthalein colourlessblue 10.0  9.3-10.5

A mixture of pH dependent chromophores/indicators may be used in thepresent invention.

The amount of the pH dependent chromophore/indicator present in thecomposition will vary depending on the extinction coefficient/colourintensity of the indicator required. The amount of pH dependentchromophore having a UV-vis spectrum that changes with pH in the range 1to 14 required is that sufficient for a discernable change in colour tobe observable by the human eye. Suitably, the pH dependent chromophores,or mixtures thereof, are present in the detergent composition in therange 0.0001 to 0.5 wt %, preferably 0.001 to 0.4 wt %, most preferably0.002 to 0.3 wt %.

Foam Dispensed pH Dependent Cue

The present invention is used as a liquid format where the compositionis dispensed as foam and the dispensed product interacts with theenvironment. Foam has a high surface area to volume ratio and rapidlyabsorbs air from the atmosphere resulting in a pH change of the foam. Ifthe foam is alkaline the pH of the foam decreases as carbon dioxide isabsorbed from the atmosphere. When the appropriate pH dependentchromophore is present a colour change is observed providing a visualcolour change. In this case the dispenser of the foam provides the pHchanging means by dispensing the foam to a carbon dioxide containingenvironment (the atmosphere). The bulk within the foam dispenser may ormay not be in contact with atmospheric gasses. Nevertheless, it ispreferred that the internal gaseous environment does not readilyexchange with the external gaseous environment when the dispenser is notin use. Suitable and preferred pH dependent chromophores are, forexample, phenolphthalein and thymol blue. Suitable dispensing devicesfor the foam are found in EP 03250593.5 and EP 03250595.0.

Anionic Surfactant, Non-ionic surfactant and Amphoteric Surfactants ormixtures thereof may be used in this foam aspect of the presentinvention. Examples of suitable surfactants systems that may be used forthe foam are as follows:

sodium lauryl alkyl sulphate (LAS), sodium lauryl ether sulphate (SLES)and coco amidopropyl betaine (CAPB); sodium lauryl alkyl sulphate (LAS)non-ionic (NI) and coco amidopropyl betaine (CAPB); primary alcoholsulphate (PAS), sodium lauryl ether sulphate (SLES) and coco amidopropylbetaine (CAPB); primary alcohol sulphate (PAS), sodium lauryl ethersulphate (SLES) and non-ionic (NI); and sodium lauryl alkyl sulphate(LAS) and non-ionic (NI).

The Detergent Composition

The composition preferably comprises a surfactant and optionally otherconventional detergent ingredients. It is preferred that the compositionused to make the foam comprises 0.001% wt/wt to 20% wt/wt of adetergent(s). It is most preferred that the detergent composition isalkaline. The alkalinity may be provided by, for example, sodiumhydroxide, sodium carbonate, sodium silicate, an amine, sodiumtripolyphosphate (STP) and/or zeolite. This alkalinity is preferablyprovided for by sodium carbonate and/or sodium hydroxide. The inventionin its second aspect provides an enzymatic detergent composition whichcomprises from 0.1-50% by weight, based on the total detergentcomposition, of one or more surfactants. This surfactant system may inturn comprise 0-95% by weight of one or more anionic surfactants and 5to 100% by weight of one or more nonionic surfactants. The surfactantsystem may additionally contain amphoteric or zwitterionic detergentcompounds, but this in not normally desired owing to their relativelyhigh cost. The enzymatic detergent composition according to theinvention will generally be used as a dilution in water of about 0.05 to2%.

In general, the nonionic and anionic surfactants of the surfactantsystem may be chosen from the surfactants described “Surface ActiveAgents” Vol. 1, by Schwartz & Perry, Interscience 1949, Vol. 2 bySchwartz, Perry & Berch, Interscience 1958, in the current edition of“McCutcheon's Emulsifiers and Detergents” published by ManufacturingConfectioners Company or in “Tenside-Taschenbuch”, H. Stache, 2nd Edn.,Carl Hauser Verlag, 1981.

Suitable nonionic detergent compounds which may be used include, inparticular, the reaction products of compounds having a hydrophobicgroup and a reactive hydrogen atom, for example, aliphatic alcohols,acids, amides or alkyl phenols with alkylene oxides, especially ethyleneoxide either alone or with propylene oxide. Specific nonionic detergentcompounds are C₆-C₂₂ alkyl phenol-ethylene oxide condensates, generally5 to 25 EO, i.e. 5 to 25 units of ethylene oxide per molecule, and thecondensation products of aliphatic C₈-C₁₈ primary or secondary linear orbranched alcohols with ethylene oxide, generally 5 to 40 EO.

Suitable anionic detergent compounds which may be used are usuallywater-soluble alkali metal salts of organic sulphates and sulphonateshaving alkyl radicals containing from about 8 to about 22 carbon atoms,the term alkyl being used to include the alkyl portion of higher acylradicals. Examples of suitable synthetic anionic detergent compounds aresodium and potassium alkyl sulphates, especially those obtained bysulphating higher C₈-C₁₈ alcohols, produced for example from tallow orcoconut oil, sodium and potassium alkyl C₉-C₂₀ benzene sulphonates,particularly sodium linear secondary alkyl C₁₀-C₁₅ benzene sulphonates;and sodium alkyl glyceryl ether sulphates, especially those ethers ofthe higher alcohols derived from tallow or coconut oil and syntheticalcohols derived from petroleum. The preferred anionic detergentcompounds are sodium C₁-C₁₅ alkyl benzene sulphonates and sodium C₁₂-C₁₈alkyl sulphates. Also applicable are surfactants such as those describedin EP-A-328 177 (Unilever), which show resistance to salting-out, thealkyl polyglycoside surfactants described in EP-A-070 074, and alkylmonoglycosides.

Preferred surfactant systems are mixtures of anionic with nonionicdetergent active materials, in particular the groups and examples ofanionic and nonionic surfactants pointed out in EP-A-346 995 (Unilever).Especially preferred is surfactant system that is a mixture of an alkalimetal salt of a C₁₆-C₁₈ primary alcohol sulphate together with a C₁₂-C₁₅primary alcohol 3-7 EO ethoxylate.

The nonionic detergent is preferably present in amounts greater than10%, e.g. 25-90% by weight of the surfactant system. Anionic surfactantscan be present for example in amounts in the range from about 5% toabout 40% by weight of the surfactant system.

The detergent composition may take any suitable physical form, such as apowder, granular composition, tablets, a paste or an anhydrous gel.

Bleaching Species

The present invention may be used in combination with bleaching species.These species may be, for example: a) a peroxygen bleach species aloneand/or in combination with a bleach activator and/or a transition metalcatalyst; and 2) a transition metal catalysts in a compositionsubstantially devoid of peroxygen species.

The use of bleaching catalysts for stain removal has been developed overrecent years and may be used in the present invention. Examples oftransition metal catalysts that may be used are found, for example, in:WO0148298, WO0060045, WO0248301, WO0029537 and WO0012667. The catalystmay alternatively be provided as the free ligand that forms a complex insitu. Bleach activators are well known in the art, for example TAED, andSNOBS. Peroxygen bleaching agents are also well known in the art, forexample, peracids (e.g., PAP), perborates, percarbonates,peroxyhydrates, and mixtures thereof. Specific preferred examplesinclude: sodium perborate, commercially available in the form of mono-and tetra-hydrates, and sodium carbonate peroxyhydrate. Other examplesof peroxyl species and activators are found in WO02077145 as well asother transition metal catalyst.

Other Adjuncts

Builders, polymers and other enzymes as optional ingredients may also bepresent in the detergent composition as found in WO0060045 andWO0034427.

Foam Examples

Table 1 gives formulations A to J that when made up to 100% with waterprovide suitable foaming compositions. TABLE 1 Formulation A B C D F G IJ % % % % % % % % LAS 1.5 1.5 2 2 2.5 5 3 1.5 NaOH 0.204 0.204 0.2720.272 0.34 0.68 0.476 0.204 Non Ionic 1.5 1.5 2 2 2.5 — — — (Unitol L70)LESS — — — — — — 1 1.5 Formaldehyde 0.08 0.08 0.08 0.08 0.08 0.08 0.080.08 phenolphtha- 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 leinPerfume 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 EDTA 0.3 0.3 0.3 0.3 0.30.3 0.3 0.3

1. A method of treating a textile, the textile carrying a stain, the method comprising the following steps: (i) applying a liquid detergent composition in the form of a foam to a textile, the liquid detergent composition comprising: a base, a detergent, a pH dependent chromophore, and carriers and adjuncts to 100%; (ii) waiting until the foam, as applied, has changed colour from its originally applied colour; (iii) rinsing the portion of the textile to which the foam has been applied with water; and, (iv) drying the textile.
 2. A method of treating a textile according to claim 1, wherein the base is selected from sodium hydroxide and sodium carbonate.
 3. A method of treating a textile according to claim 1, wherein the UV-vis spectrum of the pH dependent chromophore changes with pH in the range 1 to
 14. 4. A method of treating a textile according to claim 3, wherein the UV-vis spectrum of the pH dependent chromophore changes with pH in the range 7.5 to 10.5.
 5. A method of treating a textile according to claim 1, wherein the pH dependent chromophore is selected from the group consisting of: Phenolphthalein; thymolphthalein; Thymol Blue; Methyl Orange; Bromocresol Green; Methyl Red; Bromothymol Blue; and, Phenol Red.
 6. A method of treating a textile according to claim 1, wherein the pH dependent chromophore is present in the composition in the range 0.0001 to 0.5 wt %.
 7. A method of treating a textile according to claim 1, wherein the method comprises the step of dissolving a detergent concentrate in water to provide the liquid detergent composition for application.
 8. A method of treating a textile according to claim 7, wherein the detergent concentrate is selected from the group consisting of: liquid and granular solid detergent concentrates. 